"Imports of our nation's automobiles and auto parts have never damaged U.S. national security and will not do so in the future," Abe said at a news conference to mark the end of the parliamentary session.

Washington launched an investigation in May into whether imported vehicles were a threat to national security threat. Trump has repeatedly threatened to impose tariffs as a key part of his economic message, repeatedly lamenting the U.S. auto sector trade deficit, particularly with Germany and Japan.

Abe said Japanese companies built some 3.8 million cars annually in the United States, more than double the number of vehicles shipped there from Japan.

"Trade restrictions will not benefit anyone, and we will keep explaining that to the U.S. and work closely with them to ensure those tariffs are not imposed, " Abe said.

(Reporting by Tim Kelly; Editing by Alison Williams)